Apparatus for testing rubber



July 21, 1936.

R. W. ALLEN APPARATUS FOR TESTING RUBBER Original Filed June 9, 1931 5 Sheets-Sheet l Bnventor Ragmond W Rflen VEGA/WAT (Ittomegs July 21, 1936. R. w. ALLEN APPARATUS FOR TESTING RUBBER Original Filed June 9, 1931 5 Sheets-Sheet 2 Zhwentor Raymond W. mien Q Gttomegs July 21, 1936. R. W. ALLEN 2,048,314

APPARATUS FOR TESTING RUBBER Original Filed June 9, 1931 5 Sheets-Sheet 3 Imvemor RAB mond WI Allen dttomegs July 21, 1936. R w ALLEN 2,048,314

APPARATUS FOR TESTING RUBBER Original Filed June 9, 1931 5 Sheets-Sheet 4 (Ittornegs July 21, 1936. R w, ALLEN 2,048,314

APPARATUS FOR TESTING RUBBER ori inal Filed June 9, 1951 5 Sheets-Sheet 5 Ill Bmaentor I Rm mondwmlefl 40 Bu Cittornegs Patented July 21, 1936 UNITED STATES PATENT OFFICE APPARATUS FOR TESTING RUBBER Raymond W. Allen, Akron, Ohio, asoignor to The Firestone Tire Rubber Company, Akron, Ohio, a corporation of Ohio Beiiled is: abandoned appiioaiion Serial No.

543,059, June 9, 1981.

This application Septcil'ibei' 29; 1932, Serial NO. 635,359

8 Claims. (CL 13-41) The chief objects of the invention are to pro-' vide an improved apparatus for testing rubber samples by flexing the same to determine their flexure breakdown resisting qualities; for testing samples comprising layers of different kinds of rubber to determine the adhesion qualities of the union between the layers; to effect the uniformity of the flexing action by an orbital movement of one surface of the sample with respect to an opposite surface; to apply uniform determinate pressure to the sample during the testing thereof; and to provide a graph depicting the condition of the test piece during the course ofthe test. This application is a reiiling ,of my prior application Serial No. 543,059 filed June 9, 1931.

Of the accompanying drawings: Figure 1' is a front elevation of apparatus embodying the invention in its preferred form;

Figure 2 is a side elevation of the upper portion thereof, on a larger scale, as viewed from the right of Figure 1; v

Figure 3 is a section on the line 3-2 of Figure 2; Figure 4 is a section on the line 4-4 of Figure 3; Figure 5 is a view similar to Figure 4 showing the rotatable member advanced 90 degrees;

Figure 6 is asection on the line 6*! of Figure 3; Figure 'l is a section on the line 1-1 of Figure 3; Figure 8 is a perspective view of a vulcanized rubber test piece before testing;

Figure 9 is a view partly broken away of the same test piece after it has been tested;

Figure 10 is a pe ctiveyvlew of a different type of rubber test piece before testing; and

Figure 11 is a view partly broken away of the test piece shown in Figure 10 after it has been tested.

Referring to the drawings, the improved testing apparatus comprises a pair of vertical spaced apart supports or frame members It, It, the upper ends of which carry between them a bracket I l formed with a housing l2, and a bracketlike structure I! mounted upon the bracket Ii. Journaled in suitable thrust bearings l4, l4 within the housing I2 is a vertical spindle l5 upon the lower end portion of which is mounted a worm gear I! meshed with a worm II that is connected to the drive-shaft ll of a motor I9, thelatter being suspended from the under side of the bracket II. The front end of the shaft It extends through the housing l2 and is provided thereat with a hand wheel 20 by which the spindle I5 is manually turned, for a purpose subsequently to be explained.

The top of the spindle II is formed with a circular head 2|, and the topof the latter is formed with a diametrically disposed slideway 22 in which is mounted a dove-tail slide 22. The

respective ends of the slideway 22 are closed, and i0 exteriorly of the head, being squared to receive a suitable turning tool, and being provided with a calibrated dial 2! to facilitate accurate adjustment of the shaft.

A portion of the housing I2 is cut away at 26 at the front of the apparatus so as to give access to the shaft for adjusting the same, and manual rotation of the spindle I5 is eflected by means of the handwheel for bringing the squared end I of the shaft 24 opposite the opening 26 of the housing. The arrangement provides conveniently for adjusting the position of the slide 23 radially of the rotatable spindle head 2| from outside the apparatus.

As is most clearly shown in Figures 3 and 6, the slide 23 is formed with an upwardly extending post 21 which moves in an orbit about the axis of the spindle I! by reason of its eccentric relation to said axis, the diameter of the orbit being controlled by the position of the slide 23 in the spindle head 2|. Mounted upon the spindle head 2| is a table 28; a ball bearing structure 29 being interposed between the two, the bearing structure being unconfined upon the said head so as to be bodily movable relatively thereto. The 1 under side of the table 28 is axially recessed to receive the post 21 and a ball bearing structure 30 surrounds said post and engages the wall of the recess. The arrangement is such that orbital movement of the post 21 imparts similar movement to the table 28.

Orbital movement of the table, however, is effected without rotation of the table upon its axis. To this end there is provided a ring 3| upon the under side of which is journaled, at diametrically opposite points, a pair of downwardly projecting rollers 32, 32, and upon the upper side of which is journaled upwardly extending rollers 33, 33, the latter being positioned 90 degrees apart from the rollers 32. The ring 3| is supported upon two pairs of brackets 34, 34

I which are formed on the inner wall of the housing l2 near the top and at opposite sides thereof, the brackets of each pair being spaced apart to receive a roller 32 which bears against the 5 adjacent faces of said brackets. The arrangement is such that the ring is ,capable only of reciprocating movement upon the brackets '34.

The upwardly extending rollers 33 of the ring 3| engage the opposite sides of respective radial slots 35, 35 that are formed in the under surface of the table 28 at opposite sides thereof. The under side of the table also may be formed with annular recesses 35, 35, (Figure 3) to receive the nuts which hold the journals of the rollers 32 in place.

The rollers 33 prevent angular movement. of the table 28 upon its axis 21 but permit the table to reciprocate radially with relation to the ring 3|, and since the latter is arranged to reciprocate in the direction at right angles thereto, it will be obvious that orbital movement of the post 21 will produce orbital but not rotary movement of the table. A work support consisting of a block of :vood 39 is inset into the upper face of the table The work consists of a block of vulcanized rubber 40 which usually is of square shape as is clearly shown in Figure 8. During the testing operation it is held between the lower work support 39,

and a similar overlying work engaging member consisting of a block of wood M, the latter being urged against the work with determinate pressure to prevent relative movement of the work with relation to the work supports 39, 4i, and to 'assist in breaking down the work being tested.

The upper work-supporting block II is inset into the bottom face of a cylindrical head 42 that is formed on the lower end of the square shank I 43 of a vertically movable plunger 44, the upper 4 end of the plunger consisting of a stem 65 that is threaded on its end portion. The head 42 and adjacent portion of the shank 43 of the plunger are enclosed in. a bearing housing 45 that is I formed upon the bracket structure I3, the head 45 42 extending through the bottom of the housing, and the shank 43 extendingthrough a square aperture in a cover All on the top thereof, whereby angular rotativemovement of the plunger is restrained; A suitable bearing bushing 38 is mounted in the housing engaging the head 42. The stem 45 of the plunger 44 extends through a bearing bushing 89 mounted in the upper part of the bracket structure l3, and the threaded portion of the stem has mounted thereon a hand- 55 wheel 50 by means of which the plunger 44 may be manually raised or lowered, there being a ball bearing 5i mounted in the top of the bracket structure upon which the hub of the hand-wheel bears during the plunger-lifting operation.

For imparting determinate downward pressure to the plunger 44, the square shank 43 thereof is transversely apertured at 52, Figure 2, to receive a beam 53, the latter being pivotally supported 7 upon a pivot pin 54 extending through the shank.

Suspended from the respective ends of the beam 53 are rods 55, 55, the lower ends of which are connected by a yoke 55, that carries a depending rod 51 upon which is mounted a plurality of Weights 58, 58.

In order to give audible evidence of the completion of a test, a warning signal such as an electrle bell or buzzer (not shown) is provided. The hell or buzzer is electrically connected to a switch that is mounted, upon the testing apparatus, a

' stationary contact member" of the switch being mounted upon the cover plate I! of the hearing housing 68 and a movable member 5| of the switchbeing mounted upon the shank 43 of the plunger 44. The movable switch member 5| comprises a vertically adjustable contact 62 by means 5 of which the switch may be arranged sets to close and operate the warning Signal at different elevations of the plunger.

. In order to record graphically the progress of the failure of a. test piece during the testing 10 thereof, a rotatable chart 53 is provided, and an arm 54 which is pivotally mounted upon the bracket structin'e l3 at 85, and has its intermediate portion suitably connected at B5 to the plunger M, has its free end provided with an inked pen l5 6?, (Figure 2), that bears against the chart G3. The chart 63 is supported and rotated by a reduction gear device 88 that is mounted upon a laterally extending bracket 69 on'the bracket structure l3. The reduction gear device 58 is drlyen 20 by a sprocket chain 10 connected to a sprocket II on a countershait l2, and a sprocket 13 on the latter is connected by a sprocket chain ll with a suitable sprocket (not shown) on the drive shaft it of the motor 69. v 26 Operation-In the inoperative position of the apparatus, the motor i9 is motionless and the plunger M is supported in elevated position by the handwheel 50. In this position of the plung- I er the work supports 39, 4| are spaced apart suiii- 30 ciently to permit the mounting therebetween of a test piece 50. The plunger M is then lowered so that the member M engages the test piece, and the latter supports the plunger and the weights 58 suspended therefrom. The handwheel is 35 threaded upwardly on the stem a sufiicle'nt distance to permit subsequent unrestricted downward movement of the plunger during the test. The motor i9 is then set in motion to rotate the chart 63, and to rotate the spindle l5 whera;

by orbital movement is imparted to the table 28 and work support 38. Since the weight of the plunger M and the weights 58 provide sufiicient friction to prevent movement of the work as with relation to the work supports 39, M, it will be 45 seen that orbital movement of the lower work support about the ams of the upper work support will apply a kneading or flexing action to the interposed test piece. As the test proceeds the internal friction in the test piece generates suill- 5'0 cient heat to gradually lessen the resilience and rigidity of the rubber until the interior thereof becomes substantially plastic, and thus permits the plunger gradually to move downwardly.

At the conclusion of the test the test piece 55 rapidly breaks down and allows the plunger to descend quickly to a point-where the electrical contact 52 engages the electrical contact 55 and thus automatically actuates the warning 8ml! announcing the termination of the test. when m removed from the apparatus and cooled the test piece presents substantially the appearance shown in F u e 9, its sides being bulged, its thickness being diminished, and its interior being porous. 5

The apparatus is also applicable to a test of the adhesion properties of two different kinds of rubber vulcanized together. For this pu pose a test specimen 40 as shown in Figure 10 is placed in the apparatus and the procedure carried out 7 similarly to the testing of test piece ll above described. Test piece lll is formed by vulcanizing two diflerent kinds of rubber together forming a union substantially in a plane parallel to the planes of the faces to be engaged by the work 75 supports II and ll. One type of rubber may be vulcanized in the sample separating two layers of the other type of rubber as shown in Figure 10. If desired, however, the two kinds of rubber may 5' be vulcanized together in two layers only (not shown). The orbital movement of the upper surface with respect toithe lower surface while the specimen is heidmnder -compressionresultain a breaking down or the union between the two different of rubber as shown in Figure 11.

Comparativeresultswill indicate which types of rubber possess the greatest adhering properties. This type of test is especially valuable in determining the adhesion. properties of cushion gum and" tre'ad stock. as vulcanized together in the tread of a pneumatic tire. The test is also useful in determining the degree of adhesion-of a veneer solid tire construction, where the body of the tire is composed of a' heat transmitting, blow-out resisting type of rubber and is covered by a veneer of tough abrasion resisting rubber.

The apparatus is-substantially automatic in its operation, and provides an excellent simulation of the'treatment to which the rubber of solid .25 and pneumatic tires is subjected under service.

The apparatus may be modified within the scope of the appended claims which are not limited wholly to the specific construction shown and described.

What is claimed a:

1. Rubber testing apparatus comprising opposed work engaging members adapted frictionally to crime opposed surfaces of an interposed rubber test piece, means for compressing said test 35 piece between its frictionally engaged surfaces,

means for effecting orbital movement of one of said opposed surfaces with respect to the other, and means for preventing relative rotation of said opposed work engaging members.

40 2. Testing apparatus comprising opposed work engaging members adapted to support an interposed test piece of resilient material, means for efl'ecting relative orbital movement of said members, and means for preventing relative move- 45 ment between the surfaces of said test piece and the respective work engaging members and for exerting uniform pressure upon the test piece throughout a test. 4

3. Testing apparatus comprising opposed work 50 engaging members adapted frictionally to engage an" interposed test piece of resilient material, means for electing orbital, movement of one of said members about the axis of the. other member, and means for urging said members toll ward eachothertogripthetestpieee andpred1e produces orbital movement of the table,

means for preventing angular rotary movement 10 of said table during the orbital movement thereof, and means for holding a test piece in engagement with the top of the table.

5. In testing apparatus, the combination of a table, a driving spindle, a pivotal connection be- 15 tween the table and spindle, means for adjusting the said pivotal connection eccentrically or the axis of the spindle whereby rotation of the latter will cause orbital movement of the table, and means for urging a test piece of resilient mate- 20 rial against the top of the table.

6. In testing apparatus, the combination of a table, a driving spindle, a pivotal connection between the table and the spindle, means for adlusting the said pivotal connection eccentrically 2 of the axis of the spindle whereby rotation of the latter causes orbital movement of the table, means for preventing rotary movement of the table during the orbital movement thereof, and means for urging a test piece or resilient material against the top of the table.

7. A combination as defined in claim 6 in which the means for preventing rotary movement of the table comprises a non-rotatable ring engaging the table and movable relatively thereof in one direction, and movable relatively of the spindle in a transverse direction.

8. A combination as defined in claim 6 in which the apparatus comprises a support for said spindle, said support being provided with 40 fixed guides extending radially of said spindle, said table being provided with radial grooves, and said means for preventing rotary movement of the table comprising a non-rotatable ring, oppositely dispoud downwardly extending rollers thereon engaging said fixed guides so as to permit reciprocating lateral movement of the ring in one direction, and upwardly extending rollers on the ring spaced 90 degrees from the downwardly extending rollers engaging said radial grooves in the table so as to permit reciprocating lateral movement of the table with relation to the ring.

RAYMOND w. ALLEN. s5 

